Abstract
The sweep frequency impedance (SFI) meter allows us to measure the dynamic characteristics of the middle ear in adults (Fig. 1). To extend its versatility, it has been redesigned and applied to newborns. The SPL was found to show variations at around 0.26 and 1.13 kHz (Fig. 2). Although the former is probably related to the resonance of the middle ear, the source of the latter is still unclear. Modal analyses of the finite- element models of the newborn auditory system (Fig. 3) revealed that there is a resonance of the external ear canal wall at around 0.3 kHz, suggesting that the first variation of the SPL curve may be related to the resonance of their external ear canal.
